Leech Dissection: Step 1

First, the leech is anesthetized in an 8% ethanol solution. Ethanol effectively anesthetizes worms including leeches, and other small animals that breathe through their skin. However, concentrations of ethanol that are too high may harm or kill the animals.

A dark leech is lying on a human hand. The leech is about half the length of the hand's middle finger.
A dissecting microscope is set up on a lab bench. The microscope is positioned over a long, clear dissecting dish. The dish is filled with red wax and is illuminated by a bright light.